#include<stdio.h>
#include<string.h>

char* my_strchr(const char* s, char c)
{
	while (*s++)
	{
		if (*s == c)return s;
	}
	return NULL;
}
int main()
{
	char ch[] = "hello world";
	char c = 'l';
	//char* p = strchr(ch, c);
	//char* p = my_strchr(ch, c);
	//printf("%s\n", p);
	char ch2[] = "el";
	char* p = strstr(ch, ch2);
	printf("%s\n", p);
	return 0;
}